diff --git a/.gitea/workflows/installer.yaml b/.gitea/workflows/installer.yaml
index 0dc70b3..ccb0103 100644
--- a/.gitea/workflows/installer.yaml
+++ b/.gitea/workflows/installer.yaml
@@ -7,20 +7,26 @@ on:
 jobs:
   installer:
     name: Build installer
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-26.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Set up Go
         uses: https://github.com/actions/setup-go@v4
         with:
           go-version: '>=1.20.1'
-      - uses: cachix/install-nix-action@v27
+      - uses: DeterminateSystems/determinate-nix-action@v3
         with:
-          github_access_token: ${{ secrets.GH_PULL_TOKEN }}
-          extra_nix_config: |
+          # Gitea will supply a token in GITHUB_TOKEN, which this action passes to
+          # Nix (as access-tokens) when downloading from GitHub
+          github-token: ${{ secrets.GH_PULL_TOKEN }}
+          extra-conf: |
             # Make sure we're using sandbox
             sandbox-fallback = false
 
+            # Determinate performance features
+            lazy-trees = true
+            eval-cores = 0
+
             extra-substituters = https://nix-cache.nul.ie
             extra-trusted-public-keys = nix-cache.nul.ie-1:BzH5yMfF4HbzY1C977XzOxoPhEc9Zbu39ftPkUbH+m4=